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General Mach Discussion / Mach 3 on Tormach laser is not proceeding past M3

« on: February 06, 2022, 04:21:41 PM »

I have a Mach 3 driven Tormach machine that I converted to a laser a while back and recently I wanted to see if I could cut down on the dwell time that is built into the spindle on time and off time.  I'm using a 5 volt signal to the laser which comes from the spindle at full rpms.  I have physically removed the spindle and simply use the wires J1-1 and J1-2 on the PCNC Control board to get that signal.  The VFD is not even connected.  It worked fine, but someone online had noticed how slow the laser was.  The titanium part I was cutting in a video had lots of short cuts with stops and starts between them.  The stops and starts all seem to have delays built in.  I decided to investigate and try to reduce that non-productive time.

It seems that I must have had an old .XML file that I used as a backup that I renamed to be the actual working file, and now I can't get it to work properly.  Somehow I screwed up on my files while trying different parameters and my Tormach is in a permanent dwell while it tries to get "up to speed".  I can press the cycle start button again to get past it, but it seems that I must have messed up some settings that were allowing it to work.  Some of my other .XML trials were worse, most not responding to an M3 at all.  I think it has to do with pulleys and ramp up speeds and such.  If the spindle was actually there, going from 0 to 5140 rpm would take some time.  I can't seem to get a combination of parameters to get it to work again.

My original thought was to use the M7 (mist coolant on) command to turn it on, but I use M8 (coolant on) for argon, and I believe they are actually the same relay.  I don't know if there might be some other work around with an M code, or if I just need to be saddled with the 1/2 second delay from the spindle-on signal.  Right now, the 1/2 second delay would look pretty good compared to not getting past the M3 dwell at all!  (The additional dwell numbers that are shown in the setup screen are all at zero.)

Any insight on what to try would be appreciated.

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Show"N"Tell ( What you have made with your CNC machine.) / Laser cut titanium handcuff ring

« on: December 21, 2012, 08:28:25 PM »

Here's a new ring I made today.  It's a WORKING handcuff ring made in titanium.  It clicks closed like normal and has a tiny key that actually opens it.  I made it to bottom out at a specific ring size so it would not get too tight.  It was cut from four thicknesses of .051" 6al4v titanium plate with my Mach 3 controlled fiber laser, and was laser welded before finishing.

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General Mach Discussion / offsets

« on: November 09, 2012, 11:11:41 PM »

I have a fiber laser that I can cut things like earrings from a sheet.  It is easiest to write code for a single one then move the machine to a clear spot and cut another.  On my Anilam control, I could simply move the axis, like X0.8 Y0.1 then use a G92 X0 Y0 command to make that become the new zero point.  Mach 3 seems to do that in MDI mode but not in the code.  I'm sure there must be a simple way to do that.  Can anyone help?

Thanks.
Bruce Boone

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General Mach Discussion / Laser build

« on: September 03, 2012, 09:36:24 PM »

Hi, I'm a new poster and have a Tormach 1100 that I'm retrofitting to become a fiber laser cutter.  I make titanium rings for a living and was looking for a powerful cutting laser.  I found that I wasn't using my Tormach much, as I also have a full size machining center and CNC lathe.  The cost of a finished cutting laser was well past the mid 6 digits, so I decided to attempt it myself.  I bought the fiber laser engine, and I'll be mounting a large laser head to the Z axis and will be doing a full sheet metal enclosure to block stray infrared.

The main challenge as I see it will be to get the capacitive height sensing circuit in the laser head to work.  The Tormach uses steppers, and the height sensor will output a DC voltage corresponding to how far away from a grounded sheet, eg. 1v for 1mm away, 2V for 2mm away, etc.  It sounds to me that it might be a simple thing to get that to work with a servo, but not necessarily so with a stepper.  My question is would it be easier to have my Z axis convert from stepper that's spec'ed with the machine to servo and use the output of the sensor as the driver for Z?  I know nothing about what it would take to do that.  Maybe there's another clever way to do it that won't take much reworking or reconfiguring the machine.  I am new to the electrical workings of the machines, although I'm pretty good on the g-code end.  I can certainly use some insight on the best way to go on that.  I can get by with programming Z for flat stuff short term, but I also plan on using it for titanium rings on a rotary axis that change thickness as they go around.  Is there an add on product or macro that might accomplish this?

Another smaller issue is that my rings are pretty close to 1" diameter, so it makes sense to always draw my rotary stuff as if it were flat and simply scale my artwork until it's exactly 3.6" tall.  Is there a simple way to have the rotary axis simply think it is a Y axis so that it is based on 3.6" and no feedrate calculations are necessary?  By scaling the artwork itself to exactly 3.6", it will always perfectly line up, as any diameter calculation errors will show up in a big way when the kerf is only .002".  I run a tabletop MicroKinetics machine this way with good results.  It doesn't even know it has a rotary axis.  I would like to set up my Tormach to do that.  It has an A axis, whereas my tabletop mill has no powered Y axis, so in the Tormach case, I would actually need to keep a working Y axis as well as an A axis that would look the same in CAD.  The difference would be in the g-code only.  The Tormach setup doesn't look to allow me flexibility in setting up axes like this, but maybe someone here will have some insight to that as well. 

Another thing I would like to tweak is the rotary axis speed.  I replaced the large 6" Tormach rotary axis with a small 3" Sherline rotary.  It will have more clearance for the laser head, less friction, and will have no cutting forces on it.  Right now it takes over a minute to do a full revolution.  Ideally I'd like to speed that up considerably and run it as it were a 3.6" linear axis.  I don't see any way to do that from within the Tormach software.  The laser itself will be capable of cutting about 40"/minute in that thickness.

Thanks for any input.